A power protection and distribution assembly is typically installed at every building, factory, or similar facility, where the main electrical power from the grid enters the facility. The power protection and distribution assembly, sometimes referred to as “switchgear,” usually includes an enclosure with a main circuit breaker at the electrical point furthest upstream, or closest to the external main power grid; a power distribution bus, which may comprise copper bars for each positive power phase and one or more ground bus bars; and one or more area circuit breakers, each protecting an electrical circuit distributing power to an area of the facility. The purpose of the circuit breakers is to protect downstream circuits from overcurrent conditions, such as would occur in the event of a short circuit.
A trip system trips a circuit breaker upon the detection of an overcurrent condition. One type of trip system detects an overcurrent condition by detecting excessive heat generated by large currents moving through resistive conductors. While such trip systems will interrupt a faulty circuit in time to avoid a fire, sensitive downstream electrical equipment may still be damaged by the overcurrent condition prior to current flow interruption.
Other functions of trip systems can provide a quicker circuit interruption operation of the main breaker prior to or during dangerous arcing events through interaction with an arc flash protection system. An arc event, i.e. current traveling through air, manifests itself visibly in the form of a spark, arc, flame, glow of molten metal, etc. that results from an arcing condition. When the arc flash protection system detects such an arc event, the system may operate an auxiliary arc diverter mechanism or send a control signal to the trip system directing the trip system to trip the main circuit breaker, or both.
The arc flash protection system detects an arc event when optical or other conditions characteristic of a flash are detected. The arc flash protection system detects light as one of these conditions. The trip system detects abnormal current flowing through the conductors as another one of the arcing conditions, and signals the condition to the arc flash protection system.
With signaling between the trip system and the arc flash protection system occurring within the electrical enclosure to prevent damage from arc flash occurrences, the ability of the systems to communicate status information, and therefore provide timely and accurate circuit interruption, depends on the speed and robustness of the signaling. Providing high speed and highly robust signaling, without meaningfully increasing the complexity and/or cost of the systems, or reducing same; has heretofore proven problematic.
The Background section of this document is provided to place embodiments of the present invention in technological and operational context, to assist those of skill in the art in understanding their scope and utility. Unless explicitly identified as such, no statement herein is admitted to be prior art merely by its inclusion in the Background section.